Vacuum processing apparatus and method for producing an object to be processed

ABSTRACT

A vacuum processing apparatus  50  is provided with a bypass line  52  for causing a vacuum transfer chamber  4  and a load-lock chamber  12  to communicate with each other, and a bypass opening and shutting valve  54  for opening and shutting the corresponding bypass line  52,  wherein by opening the bypass opening and shutting valve  54,  a pressure-reduced state at the vacuum transfer chamber  4  side can be shifted to the load-lock chamber  12  side, and the pressure reduction of the load-lock chamber  12  can be carried out in a short time.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vacuum processing apparatus thatcarries out prescribed processing on the surface of an object to beprocessed, in a vacuum state.

2. Description of the Prior art

Conventionally, for example, in a production process of optical discs ora production process of liquid crystal display panels, in order toexecute surface processes such as spattering, etching, baking or ashingwith respect to objects to be processed in a vacuum state, a vacuumprocessing apparatus provided with a plurality of vacuum processingchambers has been widely used (For example, Japanese Unexamined PatentPublication No. 2000-313959).

FIG. 5 and FIG. 6 show one example of a prior art vacuum processingapparatus, respectively, wherein FIG. 5 is a plan view thereof whileFIG. 6 is a longitudinally sectional view thereof.

The vacuum processing apparatus 2 is provided with a vacuum transferchamber 4, vacuum processing chambers 8 (8A through 8C) that, in apressure-reduced state, carry out prescribed surface processing (filmformation) on discs 6 (6A through 6D) being an object to be processed,and a load-lock chamber 12 that receives and transfers the discs 6between the outside 10 and the vacuum transfer chamber 4.

The vacuum transfer chamber 4 is maintained so that the interior thereofcan be maintained in a vacuum state or in a pressure-reduced state(hereinafter merely called a “pressure-reduced state”) by a first pump14. A turbo-molecular pump (TMP), etc., may be generally used as thefirst pump 14, wherein high vacuum P1 of 10⁻⁴ Pa or so can be maintainedin the vacuum transfer chamber 4.

The above-described vacuum processing chambers 8 (8A through 8C) areprovided in a plurality (in the drawing, three chambers) so as tocommunicate with or be isolated from the vacuum transfer chamber 4,wherein prescribed surface processing such as spattering, etc., iscarried out on the discs 6 which are objects to be processed.

The above-described load-lock chamber 12 is constructed so that theinterior pressure thereof is reduced from the atmospheric pressure by asecond pump 16. An oil-sealed rotary pump, etc., which can be used fromthe atmospheric pressure, maybe generally used as the second pump 16,wherein the interior pressure of the load-lock chamber 12 can be reducedfrom the atmospheric pressure to a pressure-reduced state (medium vacuumstate) P2 of several Pa.

A transfer mechanism 22 for transferring the discs 6, which are theobjects to be processed, is provided in the vacuum transfer chamber 4.The transfer mechanism 22 is composed of a rotating table 24 and a disctransfer carrier 26 that is able to hold and transfer the discs 6attached to the corresponding rotating table 24 so as to advance andretreat. The disc transfer carrier.26 concurrently acts as an openingand shutting valve between the load-lock chamber 12 and the respectivevacuum processing chambers 8 (8A through 8C) and the above-describedvacuum transfer chamber 4.

When a disc 6 is conveyed from an outside 10 into the load-lock chamber12, a second opening portion 12B at the outside 10 side is opened with afirst opening portion 12A with the vacuum transfer chamber 4 sideclosed, and the disc 6 is conveyed from the outside 10 into theload-lock chamber 12. The orientation of the conveyed disc 6 is turnedby a rotating mechanism (not illustrated), and the disc 6 is directlyheld by the disc transfer carrier 26.

Also, in the meantime, the second pump 16 still continues its rotation,and an air opening and shutting valve 20 interrupts an air line 18.

After that, the second opening portion 12B at the outside 10 side isshut, and at the same time, the air opening and shutting valve 20 isopened, wherein the interior pressure of the load-lock chamber 12 isreduced from the atmospheric pressure to a prescribed pressure-reducedstate (medium vacuum state) P2. As the pressure reduction is completed,all the disc transfer carriers 26 retreat to the rotating table 24 side,and in this state, the rotating table 24 turns by 90 degrees in thehorizontal direction. If the respective disc transfer carriers 26 arecaused to advance after the rotating table 24 is turned, the load-lockchamber 12 and the respective vacuum processing chambers 8 areinterrupted (isolated) again from the vacuum transfer chamber 4 (in astate where the held discs 6 are, respectively, moved to the adjacentchambers). After being interrupted, the air opening and shutting valve20 is shut, the processed discs 6 (discs turned in the order from 6D to6A) are discharged to the outside 10 by a rotating mechanism in theload-lock chamber 12. And, new unprocessed disc 6 (6A) is mounted in thedisc transfer carrier 26.

As a result, the disc 6 is conveyed into the vacuum transfer chamber 4and carried out therefrom via the load-lock chamber 12 in a state wherethe reduced pressure (high vacuum state) P1 in the vacuum processingchambers 8 is maintained.

In such a prior art vacuum processing apparatus 2, the interior pressureof the load-lock chamber 12 is reduced to a prescribed pressure-reducedstate P2 by only the second pump 16, using a considerably long period oftime (T1). At this stage, the disc transfer carrier 26 is caused toretreat, and the first opening portion 12A is opened, wherein the discs6 are transferred.

If the first opening portion 12A is opened since the prescribedpressure-reduced state P2 is considerably higher than the pressure P1 ofthe vacuum transfer chamber P1, the pressure of the vacuum transferchamber 4 and the respective vacuum processing chambers 8 connectedthereto is accordingly raised.

For this reason, since there is a fear that an adverse effect due to anincrease in pressure particularly after the processing in respectivevacuum processing chambers 8 is given to quality, it was necessary tocause the disc transfer carrier 26 to standby in a state where the disctransfer carrier 26 is retreated to the rotating table 24 side or beforecommencing the processing in the processing chambers. Therefore, a longcycle time was required.

Generally, in order to secure the quality of a surface treatment of anobject to be processed, in this type of vacuum processing apparatus, (1)the pressure of the vacuum processing chambers is maintained to be lowin the vacuum processing chamber, (2) the remaining gas is quicklyexhausted smoothly, or (3) in order to prevent the quality of theobjects to be processed from being lowered immediately after the surfaceprocessing, it is necessary that the above-described pressure is devisedso that the pressure is raised as little as possible in the vacuumtransfer chamber. On the other hand, (4) it becomes another importantobject to shorten the cycle time.

In view of increasing the basic performance of the pump, a considerableeffect can be recognized with respect to any one of the above objects.This is directly connected to an increase in costs. If the dischargetime is set longer even in a case where the same pump is used, an effectcan be recognized in the above-described points (1) through (3).However, this reverses the effect with respect to shortening of thecycle time.

In connection with point (3), prior to causing the load-lock chamber andthe vacuum transfer chamber to communicate with each other, it iseffective to reduce the pressure of the load-lock chamber to apressure-reduced state close to that of the vacuum transfer chamber inadvance. However, herein, a concrete problem arises.

That is, in this type of vacuum processing apparatus, the load-lockchamber is temporarily returned to the atmospheric pressure once everycycle due to its construction. At this moment, no wide-range pump hasbeen developed, which is able to reduce the pressure from theatmospheric pressure to a pressure-reduced state at a level required forthe vacuum transfer chamber by a single unit in a short time such asseveral seconds. Therefore, even if the pressure is reduced with alonger period of time taken, the pressure cannot be reduced to apressure-reduced state at a level required for the vacuum transferchamber due to shortage in the performance of a pump.

Therefore, in order to lower the pressure of the load-lock chamber to apressure-reduced state at a level required for the vacuum transferchamber, at present, at least two types (two units) of second pumps arerequired, wherein it is unavoidable to remarkably increase costs and toincrease the area of occupancy.

Furthermore, if the object of making the discharge of the remaining gassmooth in point (2) is taken into consideration, the problem is furthercomplicated.

“Remaining gas” is the general term of gases emitted from the wallsurface of the vacuum processing chambers and vacuum transfer chamber,substrates of objects to be processed, and formed film layers, etc. In anarrow sense, the remaining gas means an “adverse remaining gas”, whichadversely influences the quality of the surface processing, among theabove. The remaining gas can be qualitatively decreased by lowering thepressure. However, the remaining gas cannot be smoothly decreased byonly control of the pressure. If the remaining gas is increased, thequality of products will be resultantly worsened. Recently, this hasbecome a serious problem as one of the issues concerning this type ofapparatus.

SUMMARY OF THE INVENTION

The present invention was developed in order to solve such conventionalproblems, and it is therefore an object of the invention to provide avacuum processing apparatus that is able to maintain the pressure of thevacuum transfer chamber at a low level without accompanying a largeincrease in the costs thereof, has high exhaust (purge) performance of aremaining gas, and is able to shorten the cycle time of respectiveprocesses.

The present invention solves the above-described problems by inventing avacuum processing apparatus according to the construction described inthe following point (1).

(1) A vacuum processing apparatus is featured in that the same includes:a vacuum transfer chamber whose interior can be maintained in a vacuumstate or a pressure-reduced state; a plurality of vacuum processingchambers that are disposed adjacent to the above-described vacuumtransfer chamber so as to communicate therewith or be isolatedtherefrom, and carry out prescribed processing on an object to beprocessed, in a vacuum state or a pressure-reduced state; a load-lockchamber, the interior pressure of which is reduced from the atmosphericpressure, that carries out receiving and transfer of the above-describedobject to be processed, between the outside and the above-describedvacuum transfer chamber; and a transfer mechanism, which is provided inthe above-described vacuum transfer chamber, receives theabove-described object to be processed from the above-describedload-lock chamber, and transfers the above-described object to beprocessed into the above-described plurality of vacuum processingchambers, and at the same time, moves the above-described object to beprocessed into the above-described load-lock chamber after prescribedprocessing is completed; and further comprises: a bypass line forconnecting the above-described vacuum transfer chamber to theabove-described load-lock chamber; a bypass valve for opening andshutting the above-described bypass line; a first opening and shuttingvalve for opening and shutting between the above-described load-lockchamber and the above-described vacuum transfer chamber; and a secondopening and shutting valve for opening and shutting between theabove-described vacuum processing chambers and the above-describedvacuum transfer chamber; wherein, when the atmospheric pressure in theabove-described load-lock chamber is reduced to a prescribed stage withthe above-described first opening and shutting valve closed, theabove-described load-lock chamber and the above-described vacuumtransfer chamber are caused to communicate with each other by theabove-described bypass valve and the above-described bypass line in astate where the above-described vacuum processing chambers are isolatedfrom the above-described vacuum transfer chamber by the above-describedsecond opening and shutting valve.

In the invention, the load-lock chamber is caused to communicate withthe vacuum transfer chamber, whereby reduction of the pressure of theload-lock chamber can be accelerated.

The above-described construction does not require any new pump system atall, and does not need any highly efficient pump, wherein it is possibleto suppress the costs thereof.

Also, since a reduced state of the vacuum transfer chamber istransmitted to the load-lock chamber in a remarkably short time, thetime required for reduction of pressure in the corresponding load-lockchamber can be shortened to a large extent. Since the pump for thevacuum transfer chamber has a larger capacity than that of the pump forthe load-lock chamber, the total cycle time can be shortened because thepump for the vacuum transfer chamber can be used quickly.

In addition, since the pressure of the load-lock chamber can be loweredto a low-pressure level without preparing two types of pumps and thedifference in pressure is small, stability of the pressure-reduced statein the vacuum transfer chamber can be improved.

A pressure rise in the vacuum transfer chamber due to communication ofthe bypass line does not influence the vacuum processing chamber side(because the vacuum processing chambers are isolated from the vacuumtransfer chamber. Therefore, stabilized surface processing in apressure-reduced state can be continued in the vacuum processingchambers as it is.

Further, since it is possible to cause a larger amount of air to flowinto the vacuum transfer chamber by virtue of communication of thebypass line than in the prior arts, the remaining gases can beefficiently exhausted together with the flown air (described in detaillater).

Also, the following constructions can be considered as variations of theinvention. The details thereof will be described later.

(2) The vacuum processing apparatus according to (1) is featured inthat, at the stage where the pressure of the above-described load-lockchamber reaches prescribed pressure required for the above-describedvacuum transfer chamber after the above-described bypass valve isopened, the above-described second opening and shutting valve is openedso as to clear a state where the above-described vacuum processingchambers are isolated from the above-described vacuum transfer chamber.

(3) The vacuum processing apparatus according to (1) is featured inthat, at the stage where time considered for which the pressure of theabove-described load-lock chamber reaches pressure required for theabove-described vacuum transfer chamber elapses after theabove-described bypass valve is opened, the above-described secondopening and shutting valve is opened so as to clear a state where theabove-described vacuum processing chambers are isolated from theabove-described vacuum transfer chamber.

(4) The vacuum processing apparatus according to (1) is featured inthat, immediately after prescribed processing is completed in theabove-described vacuum processing chambers after the above-describedbypass valve is opened, the above-described second opening and shuttingvalve is opened so as to clear a state where the above-described vacuumprocessing chambers are isolated from the above-described vacuumtransfer chamber.

(5) The vacuum processing apparatus according to (1) is featured inthat, at the stage where time considered for which prescribed processingis completed in the above-described vacuum processing chambers elapsesafter the above-described bypass valve is opened, the above-describedsecond opening and shutting valve is opened so as to clear a state wherethe above-described vacuum processing chambers are isolated from theabove-described vacuum transfer chamber.

(6) The vacuum processing apparatus according to any one of (1) to (5)is featured in that the above-described transfer mechanism is mainlycomposed of a rotating table and a plurality of transfer carriers of theobject to be processed that are attached to the above-described rotatingtable so as to freely advance and retreat, and are able to hold andtransfer the above-described object to be processed, and theabove-described transfer carriers concurrently act as theabove-described first and second opening and shutting valves.

(7) The vacuum processing apparatus according to any one of (1) to (6)is featured in further comprising: a second bypass line for causing aspecified vacuum processing chamber of the above-described plurality ofvacuum processing chambers to communicate with the above-describedload-lock chamber; and a second bypass valve for opening and shuttingthe above-described second bypass line; wherein the above-describedsecond bypass valve is opened after the above-described bypass line isopened so as to clear the above-described second bypass line is causedto communicate with the above-described load-lock chamber.

(8) The vacuum processing apparatus according to any one of (1) to (7)is featured in that an opening and shutting valve for opening andshutting an air line between the above-described load-lock chamber and apump to reduce the pressure of the above-described load-load chamber isdisposed in the above-described air line; and an accumulator capable ofaccumulating negative pressure is disposed in the above-described airline at the above-described pump side of the above-described opening andshutting valve.

(9) A vacuum processing apparatus includes: a vacuum transfer chamberwhose interior can be maintained in-a vacuum state or a pressure-reducedstate; a plurality of vacuum processing chambers that are disposedadjacent to the above-described vacuum transfer chamber so as tocommunicate therewith or be isolated therefrom, and carry out prescribedprocessing on an object to be processed, in a vacuum state or apressure-reduced state; a load-lock chamber, the interior pressure ofwhich is reduced from the atmospheric pressure, that carries outreceiving and transfer of the above-described object to be processed,between the outside and the above-described vacuum transfer chamber; anda transfer mechanism, which is provided in the above-described vacuumtransfer chamber, receives the above-described object to be processedfrom the above-described load-lock chamber, and transfers theabove-described object into the above-described plurality of vacuumprocessing chambers, and at the same time, moves the above-describedobject into the above-described load-lock chamber after prescribedprocessing is completed; wherein an accumulator mechanism, having atleast one accumulator chamber that is able to be maintained in a vacuumstate or a pressure-reduced state, which is able to accelerate reductionin pressure of the above-described load-lock chamber by negativepressure of the above-described accumulator chamber in the process ofreducing the pressure inside the above-described load-lock chamber, isprovided with respect to the above-described load-lock chamber.

(10) The vacuum processing apparatus according to (9) is featured inthat the capacity of the above-described accumulator is made by 0.5through 3 times greater than the capacity of the above-describedload-lock chamber.

(11) A method for producing an object to be processed, which carries outprescribed processing in a vacuum state or a pressure-reduced state,using a vacuum processing apparatus is featured in including: a vacuumtransfer chamber whose interior can be maintained in a vacuum state or apressure-reduced state; a plurality of vacuum processing chambers thatare disposed adjacent to the above-described vacuum transfer chamber soas to communicate therewith or be isolated therefrom, and carry outprescribed processing on an object to be processed, a load-lock chamber,the interior pressure of which is reduced from the atmospheric pressure,that carries out receiving and transfer of the above-described object tobe processed, between the outside and the above-described vacuumtransfer chamber; and a transfer mechanism, which is provided in theabove-described vacuum transfer chamber, receives the above-describedobject from the above-described load-lock chamber, and transfers theabove-described object into the above-described plurality of vacuumprocessing chambers, and at the same time, moves the above-describedobject into the above-described load-lock chamber after prescribedprocessing is completed; and comprising: a bypass line for connectingthe above-described vacuum transfer chamber to the above-describedload-lock chamber; and a bypass valve for opening and shutting theabove-described bypass line; and further comprising the step of causingthe above-described load-lock chamber to communicate with theabove-described vacuum transfer chamber in a state where theabove-described vacuum processing chambers are isolated from theabove-described vacuum transfer chamber when the pressure of theabove-described load-lock chamber is reduced from the atmosphericpressure to a prescribed pressure level.

(12) A method for producing an object to be processed, is featured inthat comprising the steps of: conveying and carrying out an object to beprocessed, from a vacuum transfer chamber, the interior of which is ableto be maintained in a vacuum state or a pressure-reduced state, to aplurality of vacuum processing chambers, which are disposed adjacent tothe above-described vacuum transfer chamber so as to communicatetherewith or be isolated therefrom and carry out prescribed processingwith respect to the above-described object to be processed, in a vacuumstate or a pressure-reduced state; receiving and transferring theabove-described object between the outside and the above-describedvacuum transfer chamber via a load-lock chamber, the interior pressureof which is reduced from the atmospheric pressure; wherein conveyance,carrying-out, receiving and transfer of the above-described object to beprocessed are executed by a transfer mechanism secured in theabove-described vacuum transfer chamber, the above-described load-lockchamber is isolated from the vacuum transfer chamber when receiving theabove-described object from the outside and transferring the samethereto, and is made open to the atmospheric air, and theabove-described vacuum transfer chamber is interrupted from theatmospheric air when receiving the above-described object from theabove-described vacuum transfer chamber and transferring the samethereto, and the interior pressure thereof is reduced, and theabove-described object to be processed is conveyed to theabove-described load-lock chamber after having executed prescribedprocessing on the above-described object to be processed with theabove-described plurality of vacuum processing chambers made vacuum; andwhen the pressure of the above-described load-lock chamber is reducedfrom the atmospheric pressure to a prescribed stage, the above-describedload-lock chamber is bypassed to the above-described vacuum transferchamber in a state where the above-described vacuum processing chambersare isolated from the above-described vacuum transfer chamber.

(13) The method for producing an object to be processed, according to(12) is featured in that, at the stage where the pressure of theabove-described load-lock chamber reaches the pressure required for theabove-described vacuum transfer chamber in the bypassed state, a statewhere the above-described vacuum processing chambers are isolated fromthe above-described vacuum transfer chamber is cleared.

(14) The method for producing an object to be processed according to(12) is featured in that, at the stage where time considered for whichthe above-described load-lock chamber reaches pressure required for theabove-described vacuum transfer chamber elapses in the bypassed state, astate where the above-described vacuum processing chambers are isolatedfrom the above-described vacuum transfer chamber is cleared.

(15) The method for producing an object to be processed according to(12) is featured in that, immediately after prescribed processing iscompleted in the above-described vacuum processing chambers in thebypassed state, a state where the above-described vacuum processingchambers are isolated from the above-described vacuum transfer chamberis cleared.

(16) The method for producing an object to be processed according to(12) is featured in that, at the stage where time considered for whichprescribed processing is completed in the above-described vacuumprocessing chambers elapses in the bypassed state, a state where theabove-described vacuum processing chambers are isolated from theabove-described vacuum transfer chamber is cleared.

(17) The method for producing an object to be processed according to anyone of (12) to(16), wherein at least a part of the above-describedplurality of vacuum processing chambers is bypassed to theabove-described load-lock chamber simultaneously with commencement ofthe bypassed state or immediately thereafter.

(18) The method for producing an object to be processed according to anyone of (12) through (17) is featured in that negative pressure of anaccumulator that is able to accumulate negative pressure is applied intothe load-lock chamber when reducing the pressure of the above-describedload-lock chamber.

According to the invention, it is possible to obtain a vacuum processingapparatus that, without accompanying a large increase in costs with asimple structure, is able to shorten the cycle time of respectiveprocessing while always maintaining the pressure of the vacuum transferchamber and vacuum processing chambers at a low level, and is able tobring about high exhaust efficiency of the remaining gases.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a roughly longitudinally sectional view schematically showinga vacuum processing apparatus according to the first embodiment of thepresent invention;

FIG. 2 is a block diagram showing a control system of the same vacuumprocessing apparatus;

FIG. 3 is a roughly longitudinally sectional view schematically showinga vacuum processing apparatus according to the second embodiment of thepresent invention;

FIG. 4 is a roughly longitudinally sectional view schematically showinga vacuum processing apparatus according to the third embodiment of thepresent invention;

FIG. 5 is a roughly fragmentary cross-sectional view schematicallyshowing a prior art vacuum processing apparatus;

FIG. 6 is a roughly virtical sectional view of the above-described priorart vacuum processing apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a detailed description is given of embodiments of theinvention on the basis of the accompanying drawings.

FIG. 1 shows a first embodiment of the invention.

A vacuum processing apparatus 50 according to the first embodiment hasno special difference from the prior art vacuum processing apparatus 2described above, other than the facility related to pressure reductionin the load-lock chamber and vacuum transfer chamber. Therefore, partsthat are identical to those of the prior art vacuum processing apparatusare given the same reference numbers as those of the prior art vacuumprocessing apparatus, and overlapping description thereof is omitted.Herein, a detailed description is given of parts that are different fromthe prior art vacuum processing apparatus 2. This is the same as in thefollowing embodiments.

A bypass line 52 is formed between a vacuum transfer chamber 4 and aload-lock chamber 12. Also, the bypass line 52 is provided with a bypassvalve 54 that opens and shuts the corresponding bypass line 52.

That is, in the first embodiment, the vacuum transfer chamber 4 itselfwill be used as a so-called accumulator.

At the stage when pressure reduction from the atmospheric pressure inthe load-lock chamber 12 is progressed by a second pump 16 to such adegree that the pressure reduction does not impair a first pump 14 (thatis, at the stage when the pressure is reduced to prescribed pressure P3,or the time T2 corresponding thereto elapses), the bypass valve 54 isopened. Opening and shutting of the above-described bypass valve 54 arecontrolled by a control device 56 (Refer to FIG. 2). And, the controldevice 56 controls the first pump 14, the second pump 16, an air openingand shutting valve 20, and a transfer mechanism 22 (including a rotatingtable 24 and a disc transfer carrier 26), and is internally providedwith a timer to open and shut a valve described later.

Also, with respect to the timing at which the vacuum transfer chamber 4and vacuum processing chambers 8, which are isolated from each other,are caused to communicate with each other (that is, the timing forretreating the disc transfer carrier 26), it is possible to select tworepresentative timings in design in response to objects (described indetail later)

Next, a description is given of actions which are obtained by theabove-described construction. That is, a description is given of acontrol process brought about by the control device 56. Also, the disctransfer carrier 26 is called the first opening and shutting valve whenthe load-lock chamber 12 and vacuum transfer chamber 4 are opened andshut, and is called the second opening and shutting valve when thevacuum transfer chamber 4 and vacuum processing chamber 8 are opened andshut.

As pressure reduction from the atmospheric pressure in the load-lockchamber 12 is caused to advance to some degree (that is, pressure P3 isreached or the time T2 corresponding to the pressure P3 after commencingthe reduction elapses), the bypass valve 54 is opened. The pressurereduction shifts to a pressure-reduced state equivalent to pressure highvacuum level P1 at the vacuum transfer chamber 4 side at the moment whenthe bypass valve 54 is opened. Therefore, the pressure in the load-lockchamber 12 is reduced to pressure P4 that is remarkably lower than thepressure P2 in the prior art at once. Therefore, in comparison with theprior art construction in which the pressure of the load-lock chamber 12is reduced by a function of only the second pump 16, it is possible toshorten the time required for reduction of pressure in the correspondingload-lock chamber 12.

In addition, since the first pump 14 for the vacuum transfer chamber 4has a higher capacity than that of the second pump 16, it is possible toshorten the total cycle time because the first pump 14 can be usedquickly. In the case of the same cycle time, a higher vacuum pressureenvironment can be achieved.

The construction does not require a new pump system at all, and does notneed any higher performance pump. Many of the conventional componentscan be used as they are, wherein it is possible to prevent costs frombeing increased.

The pressure P4 of the vacuum transfer chamber immediately after thebypass valve 52 is opened by the bypass valve 52 is slightly higher thanpressure P1 since a pressure-reduced state shifts to the load-lockchamber 12 side. However, since the respective vacuum processingchambers 8 are maintained to be airtight by the disc transfer carrier26, which is concurrently used as the opening and shutting valve, thepressure of the vacuum processing chambers 8 will not rise beyond thepressure P1. Accordingly, no adverse effect due to an increase in thepressure of the vacuum transfer chamber 4 exerts on the processing inthe corresponding vacuum processing chambers 8.

In addition, since the first opening and shutting valve is opened forthe period during which the vacuum transfer chamber 4 and the load-lockchamber 12 connected thereto recovers from P4 to prescribed pressure P1,air is efficiently exhausted from the vacuum transfer chamber 4 by thefirst pump 14 at high speed (due to the existence of a greater amount offlown air than in the prior art because P3<P2), wherein the remaininggases can be smoothly exhausted (purged). The action is one of the mostimportant actions of the present embodiment. A slight detaileddescription is given of the action below.

As a general theory, as the pressure of the load-lock chamber 12 islowered from P2 in the prior art to P4, a rise in pressure (P1-P4) ofthe vacuum transfer chamber 4 is made small when a first opening portion12A of the load-lock chamber 12 is opened to carry in and carry out adisc 6, and the pressure in the vacuum transfer chamber 4 is stabilizedequivalent thereto. This in and of itself is favorable.

However, on the other hand, “Exhaust speed of pump”has a feature bywhich the further the pressure is drawn near the arrival pressure of thepump, the smaller the exhaust speed thereof becomes. Therefore, in acase where such stabilized pressure is maintained, a problem arises, bywhich the exhaust of the remaining gases is not rather smoothlyperformed. That is, it is not always most favorable, in view ofexhausting the remaining gases of the vacuum transfer chamber 4, thatthe vacuum transfer chamber 4 is stable in a highly vacuum state wherethe pressure hardly changes.

However, in the present embodiment, a lowering (P2→P4) in the pressureof the load-lock chamber 12 is achieved not by strengthening the secondpump but by causing the vacuum transfer chamber 4 and the load-lockchamber 12 to communicate with each other via the bypass line 54. Forthis reason, it is possible to cause a large amount of air to flow intothe vacuum transfer chamber 4 on the basis of a greater pressuredifference (P1-P3) than the pressure difference (P1-P2) in the priorarts by communication of the bypass line 54, wherein it is possible toexhaust the flown air together with the remaining gases by the firstpump 14 (at a greater efficiency than in the prior arts).

When setting the timing for causing the vacuum transfer chamber 4 andthe vacuum processing chambers 8, which are isolated from each other, tocommunicate with each other (that is, the timing for commencing theretreating of the disc transfer carrier 26 as the second opening andshutting valve), it is possible to select two types of timings inresponse to objects as described above. In either case, the followingeffects can be brought about.

One of the timings to be selected is “the time when the pressure level(initial value P4) of the load-lock chamber 12 and vacuum transferchamber 4, which communicate with each other, reaches pressure P1 ofhigh vacuum required for the corresponding vacuum transfer chamber 4 (orwhen the time considered at which the pressure is reached elapses)”, andanother timing thereof is “the time immediately after surface processingin the vacuum processing chambers 8 is completed after the communicationis carried out (or when the time considered at which the surfaceprocessing is completed elapses)”.

When the second opening and shutting valve is opened and the timing whenthe vacuum transfer chamber 4 and vacuum processing chambers 8, whichare isolated from each other, are caused to communicate with each otheris set to “the time when the pressure of the load-lock chamber 12 andvacuum transfer chamber 4 reaches pressure P1”, even if the firstopening portion 12A is opened, the pressure of the vacuum transferchamber 4 will not rise from pressure P1 since the pressure of both thevacuum transfer chamber 4 and the load-lock chamber 12 reaches P1,wherein the pressure of the vacuum processing chambers 8 will not risefrom pressure P1. Therefore, the disc 6 is placed in the surrounding ofpressure P1 during the processing and transferring thereof.

Accordingly, higher quality processing can be carried out whileshortening the total cycle time.

On the other hand, the timing when the vacuum transfer chamber 4 andvacuum processing chambers 8, which are isolated from each other, is setto “immediately after surface processing is completed in the vacuumprocessing chambers 8 after having communicated with each other”, thatis, “before the pressure of the load-lock chamber 12 and vacuum transferchamber 4 reaches pressure P1 (or before the time considered when thepressure reaches pressure P1 elapses)”, it is possible to restore thepressure to a prescribed pressure level P1 by utilizing the time duringwhich the rotating table 24 turns by 90 degrees. Therefore, in thiscase, the cycle time can be further shortened.

Since air in the load-lock chamber 12 is caused to flow into not onlythe vacuum transfer chamber 4 but also the vacuum processing chamber 8after surface processing is completed (during transferring of a disc 6),more efficient exhaust (purge) of the remaining gases can be carriedout, including the vacuum processing chambers.

Also, the bypass valve 54 is shut at an optional timing until the firstopening portion 12A of the load-lock chamber 12 is closed by againcausing the disc transfer carrier 26 acting as the first opening andshutting valve to advance after the disc transfer carrier 26 commencesretreating after prescribed processing is completed.

Next, a description is given of a second embodiment of the presentinvention shown in FIG. 3.

In a vacuum processing apparatus 60 according to the second embodiment,an idea for improving the exhaust efficiency (air purge efficiency) isfurther developed. For example, taking into consideration a case whereparticularly adverse remaining gases frequently occur in a specifiedvacuum processing chamber 8 (8C in the illustrated example), as shown inFIG. 3, a second bypass line 55 that causes the corresponding vacuumprocessing chamber 8C and load-lock chamber 12 to communicate with eachother, and a second bypass valve 57 for opening and shutting the secondbypass line 55 are disposed together with the bypass line 52 (notillustrated in FIG. 3) of the preceding embodiment. The second bypassline 55 is constructed so as to communicate with the load-lock chamber12 simultaneously with or with a slight delay from opening of the bypassline 52.

Accordingly, the vacuum processing chamber 8C is caused to communicatewith the load-lock chamber 12 (or the vacuum transfer chamber 4connected to the load-lock chamber 12) quicker than other vacuumprocessing chambers 8A and 8B from an optional timing during surfaceprocessing (or immediately after surface processing) through both thebypass line 52 and the second bypass line 55, whereby the remaininggases of the corresponding vacuum processing chamber 8C can be exhaustedor (purged), taking preference over the other vacuum processing chambers8A and 8B.

The construction is effective in a case where adverse effects due tostoppage of the remaining gases in the corresponding vacuum processingchamber 8C are especially large. In addition, vacuum-processing chambers8 to be connected may be provided in a plurality.

Next, a description is given of a third embodiment of the invention,which is shown in FIG. 4.

A vacuum processing apparatus 70 according to a third embodiment is suchthat, in the above-described vacuum processing apparatus 50, anaccumulator chamber 72 is disposed at the second pump 16 side of the airopening and shutting valve 20 of an air line 18.

In the third embodiment, the accumulator mechanism constructed iscomposed of the air opening and shutting valve 20 of the air line 18 andthe accumulator chamber 72.

Generally, the function of an accumulator is improved where the capacityof the accumulator-chamber 72 is large. However, if the capacity is toolarge not only is the space of occupancy increased, but also thepressure-reduced state of the corresponding accumulator chamber 70cannot be sufficiently improved in a prescribed duration of time,wherein the pressure reducing acceleration function of the load-lockchamber 12 is rather lowered. Therefore, it is preferable that thecapacity of the accumulator is equal to 0.5 times through 3 times thesubstance internal capacity of the load-lock chamber 12.

The following actions can be brought about by providing the accumulatorchamber 72.

That is, in the above-described vacuum processing apparatuses 50 and 60,while, in the above-described vacuum processing apparatuses 50 and 60,the first opening portion 12A is shut and a processed disc 6 is replacedfor an unprocessed disc 6 in the atmospheric pressure, only the airopening and shutting valve 20 of the air line 18 is shut, and the secondpump 16 does not stop but keeps rotating. This is because, even ifinstructions for the second pump 16 to rotate and stop are repeated onceevery cycle, the pressure of the load-lock chamber cannot be favorablyreduced in an intended duration of time in view of its response feature.

In other words, this means that the second pump 16 is uselessly rotatingat times other than when contributing to pressure reduction of theload-lock chamber 12.

To the contrary, in the construction according to the third embodiment,the pressure of the accumulator chamber 72 can be reduced by rotationsof the second pump 16, utilizing the time during which the second pump16 has conventionally been uselessly rotating. Therefore, it is possibleto reduce the pressure of the load-lock chamber 12 to such a level thatthe above-described bypass valve 54 can be opened immediately after theair opening and shutting valve 20 is opened. Also, where theabove-described construction is taken into consideration only in view ofaccelerating the pressure reduction of the load-lock chamber 12, if theconstruction of this section is embodied regardless of formation of thebypass line 52, the corresponding effect of accelerating the pressurereduction can be obtained.

In the construction according to the third embodiment, since thepressure reduction of the load-lock chamber 12 can be completed in aremarkably short time after the pressure reduction of the correspondingload-lock chamber 12 is commenced, the cycle time can be furthershortened.

According to the present invention, it is possible to provide a vacuumprocessing apparatus that, with a simple construction and withoutaccompanying a large increase in costs, is able to shorten the cycletimes of respective processing under the condition of maintaining thepressure of a vacuum transfer chamber at a low level, and has a highexhaust effect.

1. A vacuum processing apparatus including: a vacuum transfer chamberwhose interior can be maintained in a vacuum state or a pressure-reducedstate; a plurality of vacuum processing chambers that are disposedadjacent to said vacuum transfer chamber so as to communicate therewithor be isolated therefrom, and carry out prescribed processing on anobject to be processed, in a vacuum state or a pressure-reduced state; aload-lock chamber, the interior pressure of which is reduced fromatmospheric pressure, that carries out receiving and transfer of saidobject to be processed, between the outside and said vacuum transferchamber; and a transfer mechanism, which is provided in said vacuumtransfer chamber, receives said object to be processed from saidload-lock chamber, and transfers said object to be processed into saidplurality of vacuum processing chambers, and at the same time, movessaid object into said load-lock chamber after prescribed processing iscompleted; a first pump maintaining the vacuum transfer chamber in thevacuum state or pressure-reduced state; a second pump reducing theinterior pressure of the load-lock chamber from the atmosphericpressure: an opening and shutting valve for opening and shutting an airline between said load-lock chamber and a second pump: and a controldevice controlling the first pump the second pump and the opening andshutting valve: wherein an accumulator mechanism, having at least oneaccumulator chamber that can be maintained in a vacuum state or apressure-reduced state, which is able to accelerate reduction inpressure of said load-lock chamber by negative pressure of saidaccumulator chamber in the process of reducing the pressure inside saidload-lock chamber, is provided with between said second pump and theopening and shutting valve.
 2. The vacuum processing apparatus accordingto claim 1, wherein the capacity of said accumulator is made 0.5 through3 times greater than the capacity of said load-lock chamber.
 3. A methodfor producing an object to be processed, which carries out prescribedprocessing in a vacuum state or a pressure-reduced state, using a vacuumprocessing apparatus including: a vacuum transfer chamber whose interiorcan be maintained in a vacuum state or a pressure-reduced state; aplurality of vacuum processing chambers that are disposed adjacent tosaid vacuum transfer chamber so as to communicate therewith or beisolated therefrom, and carry out prescribed processing on an object tobe processed, in a vacuum state or a pressure-reduced state; a load-lockchamber, the interior pressure of which is reduced from atmosphericpressure, that carries out receiving and transfer of said object to beprocessed, between the outside and said vacuum transfer chamber; a firstpump maintaining the vacuum transfer chamber in the vacuum state orpressure-reduced state, a second pump reducing the interior pressure ofthe load-lock chamber from the atmospheric pressure, and a transfermechanism, which is provided in said vacuum transfer chamber, receivessaid object from said load-lock chamber, and transfers said object to beprocessed into said plurality of vacuum processing chambers, and at thesame time, carries out said object to be processed into said load-lockchamber after prescribed processing is completed; wherein furthercomprising the step of: causing said load-lock chamber to bypass withsaid vacuum transfer chamber in a state where said vacuum processingchambers are isolated from said vacuum transfer chamber when thepressure of said load-lock chamber is reduced from the atmosphericpressure to a prescribed pressure level.
 4. A method for producing anobject to be processed, comprising the steps of: conveying and carryingout an object to be processed, from a vacuum transfer chamber, theinterior of which can be maintained in a vacuum state or apressure-reduced state by a first pump, to a plurality of vacuumprocessing chambers, which are disposed adjacent to said vacuum transferchamber so as to communicate therewith or be isolated therefrom andcarry out prescribed processing with respect to said object to beprocessed, in a vacuum state or a pressure-reduced state; receiving andtransferring said object to be processed between the outside and saidvacuum transfer chamber via a load-lock chamber, the interior pressureof which is reduced from atmospheric pressure by a second pump; whereinconveyance, carrying-out, receiving and transfer of said object to beprocessed are executed by a transfer mechanism secured in said vacuumtransfer chamber, said load-lock chamber is isolated from the vacuumtransfer chamber when receiving said object from the outside andtransferring the same thereto, and is made to open to the atmosphericair, and said vacuum transfer chamber is interrupted from theatmospheric air when receiving said object to be processed from saidvacuum transfer chamber and transferring the same thereto, and theinterior pressure thereof is reduced, and said object to be processed isconveyed to said load-lock chamber after having executed prescribedprocessing on said object with said plurality of vacuum processingchambers made vacuum; and when the pressure of said load-lock chamber isreduced from the atmospheric pressure to a prescribed level, saidload-lock chamber is bypassed to said vacuum transfer chamber in a statewhere said vacuum processing chambers are isolated from said vacuumtransfer chamber.
 5. The method for producing an object to be processed,according to claim 4, wherein, at the stage where the pressure of saidload-lock chamber reaches the pressure required for said vacuum transferchamber in the bypassed state, a state where said vacuum processingchambers are isolated from said vacuum transfer chamber is cleared. 6.The method for producing an object to be processed according to claim 4,wherein, at the stage where time considered for which said load-lockchamber reaches pressure required for said vacuum transfer chamberelapses in the bypassed state, a state where said vacuum processingchambers are isolated from said vacuum transfer chamber is cleared. 7.The method for producing an object to be processed according to claim 4,wherein, immediately after prescribed processing is completed in saidvacuum processing chambers in the bypassed state, a state where saidvacuum processing chambers are isolated from said vacuum transferchamber is cleared.
 8. The method for producing an object to beprocessed according to claim 4, wherein, at the stage where timeconsidered for which prescribed processing is completed in said vacuumprocessing chambers elapses in the bypassed state, a state where saidvacuum processing chambers are isolated from said vacuum transferchamber is cleared.
 9. The method for producing an object to beprocessed according to claim 4, wherein at least a part of saidplurality of vacuum processing chambers is bypassed to said load-lockchamber simultaneously with commencement of the bypassed state orimmediately thereafter.
 10. The method for producing an object to beprocessed according to claim 4, wherein negative pressure of anaccumulator that is able to accumulate negative pressure is applied tothe load-lock chamber when reducing the pressure of said load-lockchamber.